You want to create a class Person that sets the name to "Unknown" by default if no name is given. Which constructor code correctly implements this using a default constructor?
hard📝 Application Q15 of 15
Java - Constructors
You want to create a class Person that sets the name to "Unknown" by default if no name is given. Which constructor code correctly implements this using a default constructor?
Apublic class Person {
String name;
public Person() {
name = name;
}
}
Bpublic class Person {
String name = "Unknown";
public Person(String name) {
name = name;
}
}
Cpublic class Person {
String name;
public Person(String name) {
this.name = name;
}
}
Dpublic class Person {
String name;
public Person() {
name = "Unknown";
}
public Person(String name) {
this.name = name;
}
}
Step-by-Step Solution
Solution:
Step 1: Check default constructor sets default value
public class Person {
String name;
public Person() {
name = "Unknown";
}
public Person(String name) {
this.name = name;
}
}'s default constructor sets name to "Unknown" correctly.
Step 2: Verify parameterized constructor sets name properly
public class Person {
String name;
public Person() {
name = "Unknown";
}
public Person(String name) {
this.name = name;
}
} uses 'this.name = name;' to assign parameter to instance variable.
Final Answer:
public class Person {
String name;
public Person() {
name = "Unknown";
}
public Person(String name) {
this.name = name;
}
} -> Option D
Quick Check:
Default constructor sets default value, parameterized sets given value [OK]
Quick Trick:Default constructor sets default values; use 'this' for parameters [OK]
Common Mistakes:
Assigning parameter to itself without 'this.'
Not setting default value in default constructor
Missing default constructor entirely
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